JPH06227347A - Air bag - Google Patents

Abstract

PURPOSE:To inflate and unfold an air bag so speedily in case of emergency by making an inner surface material made of specific shape holding temperature, thickness organic polymer film so as not to be completely unified with a synthetic fiber surface material. CONSTITUTION:An air bag consists of a multiplet structure between a surface material made of synthetic fiber cloth and an inner surface material made of organic polymer film being more than 250 deg.C in shape holding temperature and 5 to 100mum in thickness. In this case, this organic polymer film inner surface material is not completely unified with the synthetic fiber cloth a surface material. According to the manufacture of this air bag, for example, an outer bag is manufactured from synthetic fiber cloth by means of sewing work or the like, while an inside bag 2 is manufactured from an organic polymer film separately with a heat seal and an adhesive agent, and the organic polymer film made inside bag 2 is inserted into the synthetic fiber outer bag 1 from the inflator mounting hole part 3, then both these bags are joined with each other in the inflator mounting part.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an airbag. More specifically, the present invention relates to an airbag that is excellent in properties such as light weight, flexibility, heat resistance, and strength, has low air permeability, and can be folded and stored compactly.

[0002]

2. Description of the Related Art In recent years, various airbags have been developed in order to minimize the risk of injury to drivers and passengers in the event of a car accident, and their effectiveness has been recognized. It has become so. The airbag is normally folded and stored in the center of the steering wheel of the vehicle or the lower front part of the passenger seat. It is designed to absorb the impact received and prevent or reduce personal injury. The inflation of the airbag is performed by gas injection from a gas injection device called an inflator, which stores an ignition device, an igniting agent, a nitrogen gas supply agent, etc. in a light metal container. Usually, high temperature gas of about 300 to 700 ° C. is generated from the inflator in the airbag, so high heat resistance is required.

An air bag usually has a melting point of 200-28.
It is made by cutting general-purpose synthetic fiber cloth such as nylon 66, polyester, polyvinyl alcohol, etc. in the temperature range of 0 ° C into an air bag shape and tailoring it by sewing or the like. Has insufficient heat resistance, and when it is exposed to the above-mentioned high temperature injection gas of 300 to 700 ° C., the fibers constituting the fabric are likely to be melted or deteriorated. Therefore, conventionally, the synthetic fiber cloth (bag material) described above is coated with a heat resistant polymer such as silicone rubber or chloroprene rubber, and after cutting it, the coating layer of the heat resistant polymer is applied to the inside of the airbag. In this way, the peripheral edge of the cut piece is sewn to be an airbag.

In such a conventional air bag coated with a heat resistant polymer, since the air bag material is made of a cloth such as a woven fabric having irregularities, a pin having a thin applied layer of the heat resistant polymer is used. Holes are generated and air tightness cannot be secured sufficiently. Therefore, in order to avoid such a danger, conventionally, the thickness of the coating layer of the heat-resistant polymer has to be increased, and as a result, the warp yarn and the weft yarn constituting the woven fabric are coated with the heat-resistant polymer. However, there is a problem in that the degree of freedom is lost due to being restrained by, and thereby the strength of the entire airbag base material is reduced. Moreover, due to the thick coating of the heat-resistant polymer, it loses flexibility and becomes hard, and the airbag manufactured from such a base material becomes bulky and can be folded and stored compactly. There was a drawback that it could not be done and the weight increased.

On the other hand, in the event of an emergency such as a collision accident, it is necessary for the airbag to inflate and deploy more quickly in order to ensure the safety of passengers. It is necessary that the weight of the air bag is small and light, and that the air bag is not bulky and has high flexibility, and that the air bag smoothly pops out from the storage portion and inflates. Moreover, the airbag must be light and non-bulky so that the airbag can be compactly stored in a specific small storage portion in the vehicle and the weight of the load on the vehicle can be minimized. Therefore, conventional airbags having a thick coating layer of a heat-resistant polymer on the inner surface of the fabric and lacking in lightness, flexibility, non-bulkyness, and airtightness are not yet sufficiently satisfactory, and their improvements have not been improved. I have been asked.

[0006]

The object of the present invention is to provide excellent characteristics such as lightness, flexibility, heat resistance and strength, low air permeability, and can be folded and stored compactly. It is to provide a highly safe airbag that can be inflated and deployed.

[0007]

As a result of various investigations conducted by the present inventors, in the above-mentioned conventional airbag in which a thick coating layer of the heat-resistant polymer is provided on the synthetic fiber cloth, the heat-resistant polymer is used. Instead of applying it to the synthetic fiber cloth as a coating film, the heat-resistant polymer is formed into a thin film separate from the synthetic fiber, and the thin polymer film is not completely joined to the synthetic fiber cloth. When placed on the inner side of the airbag, it is lightweight and highly flexible, has good heat resistance and strength, yet has low air permeability, and can be folded and stored compactly. The present invention has been completed by finding that an airbag that can be obtained is obtained.

That is, according to the present invention, a surface material made of a synthetic fiber cloth and a shape holding temperature of 250 ° C. or more and a thickness of 5 to 100 μm
An air bag composed of a multi-layer structure with an inner surface material of an organic polymer film of m, characterized in that the inner surface material made of the organic polymer film is not completely bonded and integrated with the surface material made of synthetic fiber cloth. And the airbag.

An airbag is generally composed of a portion called a front side which comes into contact with a human body when it is inflated and deployed, and a rear side to which an inflator on the opposite side is attached and which is cut into an airbag form. The front side fabric piece and the rear side fabric piece are manufactured by sewing the peripheral portions of the fabric piece into a bag shape by sewing or the like.

In the airbag of the present invention, at least one of the rear side wall wall and the front side wall is made of a synthetic fiber cloth surface material and an organic polymer film which are not completely bonded and integrated. It is necessary to be composed of multiple structures with the inner surface material. In that case, the rear bag wall, which is required to have higher heat resistance, is composed of a multiple structure of a surface material made of synthetic fiber cloth and an inner surface material made of an organic polymer film, which are not completely bonded and integrated with each other. It is preferable that at least the rear side wall and the front side wall of the bag are not completely bonded and integrated to each other, and they are composed of a multi-layered structure of a surface material made of a synthetic fiber cloth and an inner surface material made of an organic polymer film. Is more preferable.

In the present invention, "the inner surface material made of an organic polymer film is not completely bonded and integrated with the surface material made of a synthetic fiber cloth" means that the inner surface material made of an organic polymer film is synthesized. When the surface material made of fiber cloth is almost completely separated from each other except a very specific part such as an inflator mounting portion to form a multiple structure, the inner surface material made of an organic polymer film and the synthetic fiber cloth are made. The case where the surface material is partially bonded to form a multiple structure. As a typical example of partially bonding to form a multi-layer structure, an inner surface material made of an organic polymer film and a surface material made of a synthetic fiber cloth are point-bonded or line-bonded and partially bonded to each other. If you are doing so. In order to give the airbag base material a certain strength and to improve the storability and expansion / deployability of the airbag, the inner surface material made of an organic polymer film and the surface material made of synthetic fiber cloth are used as a whole. It is preferable that they are partially bonded to each other, and it is particularly preferable that they are bonded by the above-mentioned point bonding or line bonding, and the point bonding is more preferable.

In the case of point bonding, the area of one point portion, the number of point bonding portions per unit area, etc. are not particularly limited and can be arbitrarily selected, but usually 1 to 10
A point adhesion density of 00 dots / cm ² is preferable and 3 to 30
0 dot / cm ² is more preferable. In that case, it is preferable that the spot-bonded portions are distributed almost uniformly over the entire airbag base material, because the physical properties of the airbag can be made uniform in general. In case of line bonding, straight line,
An arbitrary shape such as a curved line, parallel lines, a grid shape, or a ring shape can be adopted, and in this case as well, it is preferable that the line-bonded portions are distributed almost uniformly over the whole.

In addition, the organic polymer film inner surface material is point-bonded or line-bonded to the synthetic fiber cloth surface material by directly heat-sealing the organic polymer film itself to the synthetic fiber cloth surface material in the form of dots or lines. Although it may be used, it is preferable to use an adhesive from the viewpoint of not giving unreasonable stress to the surface material and the inner surface material. In that case, considering the material of the surface material and the inner surface material, the polyamide type, the polyester type are used. , Ethylene-
It is preferable to use a hot melt adhesive such as a vinyl acetate copolymer or vinylidene fluoride.

In the airbag of the present invention, there is no limitation on the synthetic fiber material constituting the surface material made of synthetic fiber cloth,
For example, a cloth made of a conventional general-purpose fiber material such as nylon, polyester, or polyvinyl alcohol, a high melting point fiber material such as polyarylate (also referred to as wholly aromatic polyester), aramid, or polyether ketone can be used. From the viewpoint of imparting lightness to the airbag, it is preferable that the synthetic fibers constituting the surface material have a strength of 8 g / d or more. Further, from the viewpoint of imparting flame retardancy to the airbag, it is preferable to use a flame-retardant fiber material by itself or to use one having a limiting oxygen index value of 23 or more by post-flame retardation treatment. In addition, as a means for forming a fabric for an airbag from such a synthetic fiber material, a generally known woven fabric,
A method such as knitting can be adopted, in which case the product of the square root of the denier of the yarns forming the fabric and the sum of the driving densities of the warp yarn and the weft yarn is 800 to 2500.
Is preferred. If the product value is less than 800, the fabric shape tends to be loose, while if it exceeds 2,500, the utilization ratio of tear strength and tensile strength is lowered, and the texture becomes hard.

In the airbag of the present invention, the organic polymer film is arranged on the inner surface side of the above-mentioned surface material made of synthetic fiber cloth, and the organic polymer film is in direct contact with the high temperature gas ejected from the inflator. Therefore, it is necessary to use a heat-resistant film having a shape-retaining temperature of 250 ° C. or higher. Here, the "organic polymer film having a shape-retaining temperature of 250 ° C. or higher" in the present invention means that the organic polymer film can maintain its film form at least up to 250 ° C., and therefore the film is heat-resistant. When it is formed from a meltable organic polymer (such as a thermoplastic resin), the melting point is 250.
It means an organic polymer film having a temperature of ℃ or more, and when the film is formed from an organic polymer which does not have a melting point and is directly pyrolyzed (for example, vulcanized rubber), the pyrolysis temperature is 250 ℃ or more. A certain organic polymer film.

The shape retention temperature of the organic polymer film is 25
When the temperature is lower than 0 ° C, the heat resistance due to the high temperature gas cannot be imparted to the airbag. As the organic polymer film, one having a shape retention temperature of 300 to 500 ° C. is more preferable.
Further, the organic polymer film needs to have a thickness of 5 to 100 μm, and if it is less than 5 μm, the risk of pinholes is increased and the pressure resistance is insufficient.
Even if it exceeds 0 μm, the heat resistance of the airbag is not so much improved, but rather the weight of the airbag is increased. The thickness of the organic polymer film is more preferably in the range of 20-60 μm.

Examples of the organic polymer film include rubbers such as silicone rubber and chloroprene rubber, polyester, nylon 66, nylon 46, crosslinked polyethylene,
Cross-linked polyvinyl chloride, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetra Although it is possible to use an organic polymer film made of fluoroethylene-ethylene copolymer, polyimide, polyarylate, etc.,
Without being limited to these, any organic polymer film having a shape retention temperature of 250 ° C. or higher and a thickness of 5 to 100 μm can be used. The method for producing the organic polymer film is not particularly limited, and the organic polymer film can be produced by a conventionally known film production technique such as extrusion molding, calender molding, and cast molding.

The method for producing the airbag of the present invention is not particularly limited, and any method can be adopted as long as it has the above-mentioned structure. In the case of a bag in which the inner surface material and the surface material made of synthetic fiber cloth are almost completely separated from each other from the organic polymer film except for a specific portion such as an inflator attachment portion, for example, an outer bag is made from the synthetic fiber cloth. Manufactured by sewing, etc., separately from that, the inner bag is manufactured from the organic polymer film by using heat seal or adhesive, and the inner bag made of the organic polymer film is attached to the inflator in the outer bag made of synthetic fiber cloth. Even if they are inserted through the holes and joined to each other at the inflator attachment part, or the synthetic fiber cloth and the organic polymer film are laminated as they are without being adhered to cut the rear and front bag pieces. Alternatively, the airbag may be manufactured by sewing the peripheral portions of the bag pieces in a state of being overlapped. Then, in this case, as shown in FIG. 1, an airbag in which the synthetic fiber cloth and the organic polymer film are separated from each other at the main body wall portion of the airbag is manufactured. In FIG. 1, 1 is an outer bag, 2 is an inner bag, 3 is an inflator mounting hole, and 4 is a vent hole.

Further, in the case of an airbag in which the inner surface material made of an organic polymer film is joined to the surface material made of a synthetic fiber cloth by point bonding or line bonding, the synthetic fiber cloth is cut before or after cutting the cloth or the like. A method for manufacturing an airbag by pre-manufacturing a multi-layer structure base material in which the organic polymer film is point-bonded or line-bonded to each other and the two parts are partially joined and the peripheral portion is sewn using the base material is adopted. be able to. Then, in this case, as shown in FIG. 2, an airbag in which the organic polymer film is partially adhered to the synthetic fiber cloth with an adhesive is manufactured. In FIG. 2, 1
Is an outer bag, 2 is an inner bag, 3 is an inflator mounting hole, 4 is a vent hole, and 5 is an adhesive. In the airbag of the present invention as shown in FIGS. 1 and 2, the inner bag made of the organic polymer film may have a structure in which the vent hole is omitted in order to prevent the bag from bursting in the vent hole portion. Good.

[0020]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In the following examples, the thickness of the organic polymer film, the tensile strength and tear strength of the synthetic fiber cloth, the appearance of the airbag, the thickness of the airbag and the expansion / deployability of the airbag are measured as described below or evaluated.

Thickness of organic polymer film : JIS L1
It was measured according to 096. Tensile strength of synthetic fiber fabric : Measured by the label strip method of JIS L1096. Tear strength of synthetic fiber cloth : Measured by the single tongue method of JIS L1096.

Appearance of the air bag : In the air bag before the expansion / deployment test, it was visually observed whether the surface portion of the synthetic fiber cloth was affected by the inner surface material applied to the inside, and it was not affected. Those evaluated as ◯ and those affected as x.

Thickness of air bag: 140 x air bag
It was folded into a 140 mm square in a double-door system, and the thickness at that time was measured.

Inflating and deploying the airbag : A commercially available inflator filled with sodium azide used in the conventional airbag system was attached to the airbag manufactured in each example, and the inflator was tested using an impact tester. Injecting gas from the air, observing the expansion and deployment at that time with the naked eye, the bag that was completely inflated and expanded instantly without damage to the airbag ○, the hot gas from the inflator damaged the bag fabric Those that did not expand and deploy smoothly were evaluated as x.

Example 1 (1) Woven fabric by a known method in which a yarn (400d / 96f) made of polyester fiber having a strength of 11 g / d is driven in the horizontal and vertical directions at a density of 45 yarns / inch, respectively. Was manufactured. Further, this woven fabric was mixed with a disperse dye in a bath (bath ratio 1:50) containing a phosphorus-based flame retardant (K19A manufactured by Meisei Chemical Co., Ltd.) at a rate of 10 g / liter.
It was treated at 0 ° C. for 30 minutes, then soaped, washed with water and dried to produce a flame-retarded dyed fabric. (2) The above dyed cloth was die-cut by a press to cut the rear side cloth piece and the front side cloth piece, and this was sewn with a sewing machine to produce an outer bag. (3) Further, the rear side and front side film pieces were cut from the organic polymer film shown in Table 2 below, and their peripheral portions were heat-sealed using a hot plate press to produce an inner bag. did. (4) An airbag having an inner volume of 45 liters by inserting the inner bag made of the organic polymer film prepared in (3) into the outer bag made of polyester fiber prepared in (2) through the inflator mounting hole portion. Was produced.

(5) As another airbag base fabric, a silicone rubber containing 0.5% of a silane adhesive on one side of the dyed fabric produced in the above (1) (X-30 manufactured by Shin-Etsu Silicone). -1597S) was applied at a rate of 70 g / cm ² , dried at 120 ° C. for 5 minutes, and then vulcanized at 150 ° C. for 8 minutes to produce a silicone rubber-coated fabric. (6) Using the silicone rubber-coated cloth produced in (5) above, the silicone rubber-coated cloth was sewn by a conventional method so that the silicone rubber-coated surface was on the inside, to produce an airbag having an internal volume of 45 liters.

When the performance of the airbag obtained in (4) and (6) above was measured or evaluated by the above method, the results shown in Table 1 below were obtained.

[0028]

[Table 1]

From the results shown in Table 1 above, the airbags of the present invention of Experiment Nos. 1 to 6 have high tensile strength and tear strength, good appearance, light weight, can be folded thinly, and can be inflated.
You can see that it is excellent in deployment.

Example 2 (1) A dyed fabric was produced in the same manner as in (1) of Example 1 except that the punching densities in the horizontal direction and the vertical direction were each 40 lines / inch. (2) A silicone rubber film having a thickness of 20 μm produced by a casting method was spot-bonded to the cloth of (1) above using an ethylene-vinyl acetate hot-melt adhesive at a spot-bonding density shown in Table 2 below. , And a multi-layer structure in which both of them were partially spotted was manufactured. (3) Using the multiple structure produced in (2) above, cutting and sewing were performed in the same manner as in (5) to (6) of Example 1 to produce an airbag with an internal volume of 45 liters. (4) When the performance of the airbag obtained in (3) above was measured or evaluated by the method described above, the results shown in Table 2 below were obtained.

[0031]

[Table 2]

From the results of Table 2 above, the point adhesion density is 1 to 1
In the case of the experiment numbers 1 to 4 which are 000 dots / cm ² ,
It can be seen that an airbag that has high tensile strength and tear strength, is light, can be folded thinly, and has excellent expansion and deployment properties is obtained.

[0033]

EFFECTS OF THE INVENTION In the present invention, since the surface material made of the synthetic fiber cloth and the inner surface material made of the organic polymer film are not completely joined and integrated with each other, the airbag is excellent in the strength utilization ratio of the cloth portion. And has high tensile strength and tear strength. Moreover, in the airbag of the present invention, instead of providing a thick coating layer of a heat-resistant polymer on the synthetic fiber cloth, a heat-resistant thin organic polymer film is disposed on the inner surface of the airbag as a heat-resistant layer. It is highly lightweight and flexible while maintaining high heat resistance and airtightness.
Therefore, it can be folded and stored compactly,
Moreover, in an emergency, it can be expanded and deployed extremely smoothly and quickly.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an airbag of the present invention.

FIG. 2 is a cross-sectional view showing another example of the airbag of the present invention.

[Explanation of symbols]

 1 Outer bag 2 Inner bag 3 Inflator mounting hole 4 Vent hole 5 Adhesive

Claims (2)

[Claims] 1. An airbag comprising a multi-layer structure comprising a surface material made of synthetic fiber cloth and an inner surface material made of an organic polymer film having a shape retention temperature of 250 ° C. or higher and a thickness of 5 to 100 μm. An airbag characterized in that the inner surface material made of the united film is not completely bonded and integrated with the surface material made of synthetic fiber. 2. The airbag according to claim 1, wherein the inner surface material is partially bonded to the surface material by point bonding or line bonding.